Various devices and methods have been traditionally used to ablate or remove unwanted polyps, tumors, lesions, and similar abnormal growths located within a patient cavity. An example of such abnormal growths is pre-cancerous polyps or tumors that commonly develop in the glands and cells that line the colon and rectum. Other examples of abnormal growths include polypoid lesions or esophageal squamous papilloma, which are rare benign tumors of the upper gastrointestinal tract, and neoplasms of the esophagus. If not removed or destroyed, such abnormal growths often advance to more severe stages and create complications in the patient. For example, malignant tumors may spread within the body beyond their original location and create life threatening conditions.
Common methods for treating abnormal intracavital growths include resection, cryotherapy, and thermal therapy. Resection, also known as excision, is the cutting of unwanted growth from the patient. For resection methods that include capture of the tissue cut away from the patient, benefits include the patient being immediately free of the unwanted tissue and the ability to analyze the removed tissue in the laboratory. Cryotherapy, also known as cryoablation, is the application of extreme cold to freeze and destroy unwanted tissue. For example, liquid nitrogen or liquid argon are used to supercool probes used to freeze unwanted tissue. Thermal therapy, also known as thermal ablation and heat ablation, is the application of heat to coagulate, cauterize and/or ablate diseased mucosal tissue. The most common form of thermal ablation is radiofrequency ablation where radiofrequency energy is applied to the unwanted tissue. Other heat therapies include microwave coagulonecrotic therapy, laser therapy, and high intensity focused ultrasound. In cryotherapy and thermal therapy, sufficient raising or lowering of tissue temperature, respectively causes necrosis of the effected tissue. For convenience, the term ablate will be used herein to describe any and all of these thermal therapy processes. In use, these devices are placed adjacent the unwanted tissue and tissue is ablated, cauterized, coagulated, frozen, or burnt, as the case may be, by energy transmitted from or to the device.
Traditional treatment devices have three primary shortcomings. First, traditional devices can ablate or resect only relatively small portions of patient tissue at one time. For example, ablation devices having a surface for ablating patient tissue by transmitting energy to or from the surface can only ablate an area of patient tissue substantially equal to the area of the transmission surface in a single energy transmission.
A second primary shortcoming of traditional treatment devices is their inaccuracy in use. A primary challenge for treating unwanted growths is to destroy or resect the targeted tissue without adversely affecting healthy adjacent or underlying cells. Regarding ablation devices especially, damage to healthy underlying esophageal muscle tissue often leads to the creation of a stricture or constriction in the esophagus. Many traditional ablation devices ablate targeted tissue without first isolating the targeted tissue from adjacent and underlying healthy tissue. As a result, when too much energy is transferred to or from the device, ablation of healthy adjacent cells and/or underlying cells can occur. On the other hand, when too little energy is transferred from the device, less than all of the targeted tissue is treated.
A third primary shortcoming of traditional devices is present with devices having resecting capability. Use of conventional resection devices allows for resection of tissue from a patient, but leaves non-cauterized, or insufficiently cauterized tissue in the patient. Non-cauterized or insufficiently cauterized tissue remaining in the patient after a resection may lead to infection or bleeding.
The conventional approaches for treating unwanted and abnormal growths requiring the precise resection and/or ablation of relatively large portions of intralumenal tissue are insufficient in these regards. Thus, there is a need for a resection and ablation device and a method for using such a device that allow accurate and minimally invasive resection and ablation, as the case may be, of relatively large amounts of intralumenal patient tissue.